Isomerization of 5-methylmetadioxanes



United States Patent U.S. Cl. 260468 12 Claims ABSTRACROF THE DISCLOSURES-methylene metadioxanes of the formula O-CH wherein R represents ahydrogen atom or a hydrocarbon radical containing 1 to 18 carbon atomsis isomerized to produce, depending on the starting metadioxane, (I) amethallylic ester of the formula H CH3 R,-COOHZ( J=CH,

or when R, in the starting metadioxane is a vinyl radical of the formula2 UHF-C- wherein R is a hydrogen atom or a lower alkyl containing 1 to 5carbon atoms, a mixture of (I) and (II) 2- methyl-4-methyleneglutaraldehyde of the formula CROSS REFERENCE TO RELATED APPLICATIONThis is a continuation-in-part application of our copending UnitedStatese patent application, Ser. No. 411,- 580, entitled, Isomerizationof Methylened-Metadioxanes filed on Nov. 6, 1964.

BACKGROUND OF THE INVENTION wherein R and R" represent an alkyl or anaryl radical, at a temperature between 250 C. and 550 C. in the presenceof a catalyst such as pumice or certain silicas.

3,444,238 Patented May 13, 1969 This isomerization process, however,produced p-alkoxyaldehyde of the following general formula R!!!RR"CHOOHz( J-CHO RlI/f SUMMARY OF THE INVENTION We have now found thatby using, as a starting material, S-methylene metadioxane in which theposition 5 is occupied by an alkylidenic substituent and at least one ofthe substituents in position 2 is a hydrogen atom in accordance with theformula as follows:

the production of an ester of a methallylic alcohol of the formula H CH3R1C-OCH2-(E=CH2 (I) Furthermore, the presence of a catalyst in theisomerization of this invention becomes optional.

We have also found that when the starting material is a S-methylenemetadioxane of the aforesaid formula in which R, is a vinyl radical 2UHF-C- wherein R represents a hydrogen atom or a lower alkyl containing1 to 5 carbon atoms, the isomerization produces, in addition to themethallylic ester of the Formula I, a new composition of matter,2-methyl-4-methylene glutaraldehyde as represented by the generalFormula II (I311, CH,

one-p-cm-ii-ono R: (11) The isomerization of this invention ispreferably carried out by subjecting the suitable metadioxane vapor to athermal molecular rearrangement at a temperature between 350 C. and 600C. for a duration between about 1 and 200 seconds to produce thecorresponding isomer as represented by the previously stated Formula Ior isomers as a mixture represented by Formula I and 11.

DESCRIPTION OF THE PREFERRED EMBODIMENT The suitable S-methylenemetadioxanes which constitute the starting materials of the presentinvention may be obtained in known ways from the reaction of anappropriate aldehyde and a diol. Preferably, they may also be producedaccording to the processes described in our copending United Statespatent application Ser. No. 620,201, filed Dec. 28, 1966, entitled,Functional Derivatives of Methylene-Z-Propanediol-l-3 and the Method forPreparing the Same. According to the methods described in our aforesaidcopending application, the starting metadioxanes for the presentinvention are prepared by reacting an a,fi-ethylenic aldehyde such asacrolein with a dienic compound (D) in a Diels-Alder reaction. Theresultant cyclic aldehyde is reacted with an alkaline medium in an aldolcondensation followed by a Cannizzaro reaction to produce thecorresponding gem-dimethylolated derivative of the following formula:

3 The hydrogen atoms in the hydroxy groups of the gemdimethylolatedderivative are substituted ;with a methylenic divalent radical to form acorresponding dienic adduct of metadioxane of the formula in which R hasthe same meaning as stated hereinabove, and thereafter the dienic adductof metadioxane is treated at a high temperature to remove the dienicgroup thereby producing the metadioxane suitable as a starting materialof this invention according to the following reaction:

OHz-O (b) The alicyclic or heterocyclic conjugated diolefins, such ascyclopentadiene and its alkylated derivatives, 1,3 cyclohexadiene,furan, etc. 'In the case, the product resulting from the reaction of thefirst stage is a bicyclic aldehyde of the formula i i a, 1 It A c\ L /CCHO 1 wherein A represents a methylene or ethylene bridge, an oxygenatom, etc., according to the diene utilized.

(c) Anthracene or its derivatives, naphthacene and other polycyclicaromatic compounds known to react as dienic partners in a Diels-Alderreaction. In the case of anthracene, the compounds obtained in the firststage are of the following type:

@ C 1 one Alternatively, metadioxanes can be prepared directly from2-methylene-1,3-propanediol by substituting the hydrogen atoms of thehydroxy groups with a methylenic divalent radical. The method ofpreparing 2-methylene- 1,3-propanediol is described in a Weiss et al.copending US. patent application Ser. No. 325,493, filed on Nov. 21,1963, entitled, A Process for Preparation of Methylene-2-Propanediol-1-3 and its Derivatives.

4 We found the metadioxanes of the type in which R is a vinyl radical asrepresented by the formula O-GH \C=CH3 can be prepared advantageouslyfrom the following compounds:

The pyrolysis of compounds (a), (b), and (0) producesS-rnethylene-Z-vinyl metadioxanes according to the following equations:

The vinyl substituted metadioxane also may be produced by reactingacrolein with 2-methylene-1,3-propanediol, according to the equation asdescribed in the aforesaid copending United States patent applications.

As stated hereinabove, R of the suitable 5methylene metadioxane is ahydrogen atom, a hydrocarbon radical or a heterocyclic radicalcontaining up to about 18 carbon atoms. Preferably the hydrocarbonradical is selected from the group consisting of alkyl, alkenyl,alicyclic, aralkyl, aralkenyl, aryl, alkaryl, including such radicalswhen inertly substituted. When R is an alkyl, it typically may be astraight chain alkyl or a branched alkyl containing 1 to 18 carbon atomsincluding methyl, ethyl-n-propyl, i-propyl, n-butyl, t-butyl, i-butyl,n-pentyl, 2-pentyl, n-hexyl, n-heptyl, 3-heptyl, n-dodecyl, andn-ocadecyl. When R is an alkenyl, it may contain from 2 to 18 carbonatoms such as vinyl, allyl, propenyl, i-propenyl, 2-

penten-Z-yl, 3 hepten-3-yl, or oleyl. When R is an alicyclic radical itmay typically contain 3 to 18 carbon atoms including radicals having 3-to lZ-membered rings such as cyclopropyl, cyclobutyl, cyclopentyl,cyclopenten-l-yl, cyclohexyl, cyclohexen-3-yl, 3-methylcyclohexen-3-yl,4- methylcyclohexen-3-yl, Z-norbornyl, and cyclododecyil. When R is anaryl, it may be phenyl or naphthyl which may be mono-, biortri-substituted by groups including alkyl containing 1 to 4 carbonatoms; halogens notably, fiuoro, chloro and bromo radicals; and hydroxy,methoxy, ethoxy, carboxy, carbomethoxy, carboethoxy and methylolradicals. For aralkyl and aralkenyl, it may be radicals in which thebenzene nucleus is inertly substituted in the same manner as the arylstated above; preferably the alkyl substituent contains 1 or 2 carbonatoms (i.e., phenylmethyl and phenylethyl) and the alkenyl substituentrepresents the vinylene group. The suitable heterocyclic radicalsinclude Z-tetrahydrofuryl, 2-furyl, 2-tetrahydropyranyl, 3,4-dihydro(2N)-2-pyranyl, 1,3-dioxolan-2-yl, 2- thienyl, and 4-pyridyl.

In the production of methallylic esters, it was found that theircorresponding metadioxanes isomerize under the sole influence of thereaction temperature. The isomerization temperature can be between 350C. to 600 C. at normal pressure. The preferred temperature for thereaction is between about 420 C. to 500 C. Temperatures substantiallybelow 350 C. lead to an undersirable slow reaction, and temperaturesabove 600 C. lead to degradation with reduced yield. When the process isconducted in the preferred temperature range, the yield of methallylicesters is very high.

The thermal rearrangement leading to the isomerization of S-methylenemetadioxane to form the corresponding methallylic ester may bepostulated as the result of a hydrogen transfer from position 2 (whichis rather unstable because of the presence of two adjacent oxygen atomsin the 6-membered ring) to the position 4 with the breakage of the 34bond by a radical mechanism depicted as follows:

It is noted that this reaction takes place for all suitable metadioxanesstated previously. However, when R of the metadioxane is a vinyl groupof the formula wherein R is a hydrogen atom or a lower alkyl containing1 to 5 carbon atoms, the configuration of the metadioxane molecule isfavorable to the transfer of a hydrogen atom from the C-4 position tothe vinyl group by a circular transfer of electrons. The hydrogen in theallylic position is also very unstable. The allyl-vinyl ether thusformed in the initial electron transfer immediately undergoes a secondcircular transfer in a Claisen rearrangement 6 which leads to theformation of the dialdehyde as depicted below.

The isomeric transformation of S-methylene-Z-vinyl metadioxane into2-methyl-4-methylene glutaraldehydes is unexpected. Under the sameconditions of reaction, the S-methylene-Z-alkyl (or aryl) metadioxanesproduces with very high yields esters of methallylic alcohol.

In the present case, a certain quantity of methallyl acrylate isobtained in the mixture emerging from the reaction zone. The2-methyl-4-methy1ene glutaraldehyde constitutes nevertheless in generalthe preponderant product of the reaction. Moreover, it has been notedthat the S-dimethyl-Z-vinyl metadioxane remains unchanged after passageof its vapors over pumice at 480 C. Whereas in passing over silica at340 C. it isomerizes into allyloxypivalic aldehyde according to amechanism entirely different from that to which the present reactionconforms.

The isomerization of the present invention is carried out advantageouslyat atmospheric or at a lower pressure, although high pressure withoutsignificant advantage can also be employed. In the preferred reactionconditions, the isomerization is carried out in vapor phase. The 5-methylene metadioxane vapor may be diluted with an inert gas such asnitrogen or carbon dioxide. Under these diversified reaction conditions,the duration of the metadioxane vapor remaining in the pyrolysis zonevaries within wide limits between about 1 and 200 seconds. In practice,a retention time of the order from 10* to 50 seconds is suitable.

Any reactor vessel suitable for high temperature vapor reaction may beused to carry out the process of the present invention. The vessel, forexample, may consist of a tube made of a material capable ofwithstanding the temperature involved, such as Pyrex glass, steel,stainless steel, nickel, Monel, etc. The vessel may be empty, but topromote heat exchange, it is preferably packed with spheres or rings ofglass, ceramics, and stainless steel. Kieselguhr, pumice, kaolin andsilicated compounds, which are weakly acidic and which appear to possessa certain catalytic effect on the isomerization may also be used. When aheat transfer material or a catalyst is used in the reaction vessel, astationary or preferably a fluidized bed may be used to promote thecontact of the solid with the reaction vapor.

At the outlet of the reaction vessel, the vapor of the pyrolysis iscondensed and the constituents are separated therefrom in known manner,such as by direct rectification. The acetal which has not beentransformed is recycled to the reactor.

In preparing the methallylic esters according to the present invention,the dienic adduct of metadioxanes may be used directly as a startingmaterial. This compound when subjected to the action of hightemperature, undergoes simultaneous pyrolysis to eliminate the dieniccom- 7 pound (D) and to transform into corresponding methallylic esteraccording to the following reaction R1 O-GHz This process efliectivelyeliminates the step of isolating the intermediate, S-methylenemetadioxanes either by directing the raw vapor emerging from thepyrolysis into a second reactor held at a suitable temperature forisomerization, or by introducing directly the dienic compound into areactor whose temperature makes it possible to eifect simultaneously thepyrloysis with liberation of the diene and also isomerization of the-methylene-2- vinyl metadioxane under the conditions of the dilution andthe contact time selected. The process thus has particular advantage inthe production of methallylic esters when the suitable dienic adductsare prepared by reacting aldehydes and diols in accordance with ourprevious patent application Ser. No. 620,201, referred to hereinabove.

In the alternative process without recovering the intermediates, thereaction conditions, temperatures, pressures, and time are the same asthose hereinabove given for the case of a simple isomerization of theacetals. Advantageously, the resultant diene (D) is separated from theester by filtration or distillation after isomerization. It is preferredto use dienic compounds containing the dienic radical (D) selected fromthe group consisting of (a) and (b) hereinabove indicated.

Methallylic esters produced in accordance with the methods are suitablefor the manufacture of synthetic polymers or resins of various typescapable of polymerizing or copolymerizing with other ethylenic monomers.

The new unsaturated dialdehydes of the invention, due to theirpolyfunctionality, have many uses particularly as intermediates fororganic synthesis. For example, they may react with the proteins orpolyhydroxylated compounds, such as the caseins, polyvinyl alcohols, andcellulosic products, to reticulate and to render the resultantmacromolecules insoluble, due to which the compounds of this inventionare particularly useful in the treatment of textiles and papers. Thedouble bond in the molecule also may yield homopolymers or copolymerswith other monomers by radical polymerization.

The unsaturated dialdehydes of this invention may be considered as asubstituted derivatives of acrolein:

This unique molecular structure enables the dialdehydes of thisinvention to react not only in a customary manner as saturatedglutaraldehydes already known but also to react in polymerization, inMichael addition reactions, and in Diels-Alder dienic synthesis. It isimportant to note that, as an intermediate, the advantage of the doublebond for many reactions is passed onto the products of the reaction,such as the corresponding diacids, the Z-methyl- 2R-4-methylene glutaricacids and their esters. Such acids and the tat-methylene glutaric estersare useful in polymerization or copolymerization with other vinylmonomers. (See US. Patent Nos. 2,522,366; 3,074,999; 3,342,853; and3,342,854.)

A number of specific examples of the invention will now be given toillustrate both the process and the products thereof.

Example I Metallylic esters were prepared by isomerization of 5-methylene metadioxanes according to the following reaction The reactorused comprised a tube of stainless steel 450 millimeters long and 17millimeters in interior diameter bent into a U-shape and immersed in abath of fused salt heated to 450-460 C. The tube was loaded with 70 cc.of pumice particles of 2 to 4 millimeter size. Using a graduated ampule,one end of the tube was connected to 'a source of nitrogen and at theother end to a water condenser having cold traps for solid which wasmaintained at a low temperature by Dry Ice and was used for the recoveryof the pyrolysis product. The series of runs to be given below, in whichthe radical R was varied, was carried out with gram charges of thereactant introduced at the upper end of the tube at the rate of 50 gramsper hour with a nitrogen current of about 10 liters per hour.

The products of pyrolysis were analyzed by gas chromatography forevaluation of the extent of isomerization and yields. The results arelisted in Table I. They were additionally subjected to a fractionaldistillation in order to isolate and characterize the methallylic estersby their infra-red spectra and their mass spectra. The structures havealso been identified by saponification of the benzoic esters andisobutyric esters, and also by the characterization of the methallylicalcohol or benzoic acid and isobutyric acid products.

1 Quantity employed-quantity recovered/quantity employed. 3 Moles ofester formed/moles of dioxane transformed.

The methallyl isobutyrate obtained have the following properties:

E20 11s.: E 146-155 c.) c 150 11 11s.; n 1.4174 1.417 4, 0.8884

For the methallyl-benzoate obtained, its characteristics were asfollows:

The isobutyric acid obtained by saponification of methallyl isobutyrateproduced a salt of S-benzylisothiouronium melting at 143 C. (literativevalue 142- 142.5 C.). The benzoic acid resulting from the methallylbenzoate fused at 122.4" C. and did not exhibit any depression of itsfusion point by mixing with a sample of authentic benzoic acid.

Example H Methallyl forrniate and benzoate were prepared by pyrolysis ofacetals of 2,2-dihydroxymethyl-S-norbornene which was produced accordingto the process described in the two above identified copending UnitedStates patents.

(a) Methallyl formiate.In a first reaction stage, cyclopentadienereacted with acrolein to form 2-formyl- S-norbornene. For the details ofthe reaction, see Roger Adams, Organic Reactions, volume 4, page 90,John Wiley & Sons, 1948. Secondly, this product was reacted withformaldehyde to obtain 2,2-dihydroxymethyl-- norbornene. These first twosteps were carried out according to the mode of operation set forth inthe Weiss et al. United States patent application above cited. In athird step, the formal spiro-5,2'-m-dioxane-5'-norbornene of this diolwas prepared according to the procedure set forth in our copendingpatent application. Lastly, this product was pyrolyzed under theconditions of Example I, the reactor being loaded with glass marblesinstead of pumice grains. The pyrolysis was substantially complete, andthe cyclopentadiene was recovered with a yield of 96%. In addition,there were obtained 19 moles of methallyl formiate and 74 moles ofS-methallyl metadioxane for 100 moles ofspiro-5,2-m-dioxane-5'-norbornene utilized to give a yield of 93% inther product of pyrolysis and isomerization. The yield in methallylformiate by reference to the metadioxane transformed amounted to 73%.

(b) Methallyl benzoate.-The process was carried out as outlined in theimmediate preceding paragraphs under (a). The 2-phenylspiro-5,2'-m-dioxane-5'-norbornene was first prepared according to themethod described in our copending application. This product was thenpyrolyzed under the conditions set forth in Example I. The pyrolysis wascomplete and 98% of the theoretically available cyclopentadiene wasrecovered. Moreover, 44 moles of methallyl benzoate and 49.5 moles ofS-methylene-2-phenyl-metadioxane for 100 moles of Z-phenylSpiro-5,2'-m-dioxane-5'-norbornene employed were recovered. This amountsto a yield of 93.5% in products of pyrolysis and isomerization. Theyield of methallyl benzoate, by referenc to the metadioxane transformed,amounted to 87%.

In contrast, when the pyrolysis was carried out at a lower temperaturebetween 400 C. and 420 C., the isomerization did not take place andthere were obtained, respectively, for 100 moles of cyclic acetal, inthe first case, 92 moles of S-methylene metadioxane and, in the secondcase, 88.5 moles of S-methylene-Z-phenyl metadioxane without anydetectable quantity of isomeric methallylic esters.

Example III 5-methylene-2-vinyl-metadioxane was introduced into the topof a stainless steel tube 450 millimeters in length and 17 millimetersin interior diameter, loaded with glass marbles and heated to between450 C. and 460 C. at a rate of 50 grams per hour. At the same time, acurrent of nitrogen at the rate of 20 liters per hour passed through thetube. The reaction products were recovered by condensation in a waterrefrigerant followed by a cold trap held cold by Dry Ice.

The test lasted for four hours. 200 grams (1.58 moles) of material wereplaced in reaction, of which 189 grams of gross products were recovered.The products, according to gas chromatography analysis, had thefollowing composition:

S-methylene-Z-vinyl metadioxane not transformed-53 grams 0.42 moles).

Methallyl acrylate38 grams (0.30 moles).

2-methyl-4-methylene-glutaraldehyde68 grams (0.54

moles).

Cutting compounds (acrolein methylene-2 propane-diol 1-3, etc.26 grams.

Nonvolatile sub-products4 grams.

73.5% of the 5-methylene-2-viny1 metadioxane em ployed had thus beentransformed. By reference to the 5-methylene-2-vinyl metadioxanetransformed the yield was as follows:

25.9% in methallyl acrylate and 46.5% in Z-methyl- 4-methyleneglutaraldehyde.

Rectification of the reaction mix at a pressure of 100 millimeters ofmercury yielded a colorless liquid fraction titrating 92% to 95% of2-rnethyl-4-methylene glutaraldehyde (dosage by kas chromatography)having the following characteristics:

E C-.. -135 E 55-56 11 1.4635 c1 0.982

Example IV Preparation of 2-methyl-4-methylene glutaraldehyde wascarried out by direct pyrolysis of the spiro-2-[(5-norbornene-Z-yle)-5,2'-metadioxane-5'-norbornene-] prepared in a boilingreaction of 61 grams (0.5 mole) of 2- formyl-S-norbornene and 77 grams(0.5 mole) of 2,2-di- (hydroxymethyl)-5-norbornene in 200 cc. of benzenein the presence of 1 gram of p-toluene sulfonic acid as a catalyst.

The water of reaction was eliminated by distillation as an azeotropicmixture along with the benzene. After the reaction, the catalyst wasneutralized by sodium bicarbonate, and the benzene was distilled. Thereaction product was obtained in the form of colorless crystals meltingat C.; the yield was 123 grams, i.e., 95 of the theoretical amount.

The spiro compound was pyrolyzed under the conditions of Example 111according to the following reaction:

0- H2 ca 3 CH5 ca 2 Q +OCH- .H-CH C The cyclopentadiene was recovered orregenerated with a yield of 94%.

The amount transformed is listed below expressed as moles of product for100 moles ofspiro-2-[I(5-norbornene-Z-yle)-5,2'-metadioxane-5-norborn.ene]

- CHO Percent 2-methyl-4-methylene glutaraldehyde 36 Methallyl acrylatel9 5-methylene vinyl metadioxane 28 This last product could beisomerized to produce 2- methyl-4-methylene glutaraldehyde by theprocess in accordance with Example 111.

and 17 millimeters in internal diameter loaded with glass beads andheated to 450 C. to 460 C. At the same time,

1 1 a current of nitrogen of 20 liters per hour was passed through thetube in order to dilute the reacting vapors.

The products of reactionwere passed into a water refrigerant functioningas a condenser followed by a cold trap cooled with Dry Ice.

95.5 grams of the pyrolysis product were recovered. Analysis thereof bygas chromatography indicated that it contained:

7. 8 grams (0.056 mole) of -methylene-2-( l-methyl vinyl) metadioxanenot transformed 35.3 grams (0.252 mole) of methallyl methacrylate 11.8grams (0.94 mole) of 2,2-dimethyl-4-methylene glutaraldehyde Byrectification of the mixture at a pressure of millimeters of mercury,the 2,2-dimethyl-4-methylene glutaraldheyde was isolated which is aliquid boiling at from 85 C. to 90 C. at 10 millimeters of mercury.

We claim:

1. A method of isomerizing S-methylene metadioxane of the formula O--CHC=CH2 O-CH2 wherein R is a hydrogen atom, a hydrocarbon radical or aheterocyclic radical having up to 18 carbon atoms which comprisessubjecting said metadioxane to the action of a high temperature betweenabout 350 C. and about 600 C. and for a duration of about 1 to 200seconds to produce (1) a methallylic ester of the formula or to producewhen R of the said metadioxane is a vinyl radical of the formula l aCHz=C- wherein R is a hydrogen atom or a lower alkyl containing 1 to 5carbon atoms, a mixture of (I) and (II) Z-methyl- 4-methylenegl'utaraldehyde of the formula on, CH2 0HoooHzCoH0 2. A method of claim1 wherein R is a hydrogen atom, an alkyl containing 1 to 18 carbonatoms, an alkenyl containing 2 to 18 carbon atoms, an alicyclic radicalcontaining from 3 to 18 carbon atoms, an aryl selected from the groupconsisting of phenyl and naphthyl, an alkaryl or a heterocyclic radicalcontaining less than about 18 carbon atoms.

3. A process according to claim 2 wherein the temperature is betweenabout 420 C. and 500 C. and said duration is between 10 seconds and 50seconds.

4. A process of claim 3 wherein the isomerization is conducted in agaseous state and in the presence of a gaseous diluent.

5. A process according to claim 4 wherein the gaseous diluent isnitrogen or carbon dioxide.

6. A method for preparing 2-methyl-4-methylene glutaraldehyde of theformula i i OHC-(i-CHz-C-CHO wherein R is a hydrogen atom or a loweralkyl containing 1 to 5 carbon atoms, said method comprising thermalisomerizing at a temperature in the range between 350" C. and 600 C. andfor a duration between 1 and 200 seconds 5-methylene-2-vinyl metadioxaneof the formula and thereafter recovering 2-methyl-4-methyleneglutaraldehyde therefrom.

7. A method according to claim 6 wherein the thermal isomerization iscarried out at 420 C. to 500 C. for a duration of 10 to 50 seconds andin the presence of nitrogen or carbon dioxide as a diluent.

8. A method of preparing a methallylic ester comprising introducing intoa reaction zone 5 -methylene-metadioxane of the formula O-OHz R1CH C=CH10-011, wherein R is a hydrogen atom, a hydrocarbon radical or aheterocyclic radical having up to 18 carbon atoms, maintaining saidmetadioxane is a gaseous state in said reaction zone at a temperaturebetween about 350 C. and about 600 C. for a duration between about 1second and about 200 seconds, and recovering therefrom the correspondingmethallylic ester isomer of the formula 0 OH; H l R.000Hz CH 9. A methodaccording to claim 8 wherein R is a hydrogen atom, an alkyl containing 1to 18 carbon atoms, an alkenyl containing 2 to 18 carbon atoms, analicyclicradical containing from 3 to 18 carbon atoms, an aryl selectedfrom the group consisting of phenyl and naphthyl, an alkaryl or aheterocyclic radical containing less than about 18 carbon atoms.

10. A method according to claim 9 wherein the temperature is betweenabout 420 C. and 500 C. and said duration is between 10 and 50 seconds.

11. A method according to claim 10 wherein the reaction is carried outin the persence of a gaseous diluent which is nitrogen or carbondioxide.

12. 2-methyl-4-methylene glutaraldehyde of the formula wherein R is ahydrogen atom or a lower alkyl containing 1 to 5 carbon atoms.

References Cited UNITED STATES PATENTS 2,820,820 1/ 1958 Montaga et al.3,271,377 9/1966 Mantell et al.

FOREIGN PATENTS 706,176 3/1954 Great Britain.'

LORRAINE A. WEINBERGER, Primary Examiner.

A. P. HALLUIN, Assistant Examiner.

US. Cl. X.R.

7 TED STATES PATENT OFFICE 1 CERTIFICAIE OF CORRECTION Patent No. 44,238DatedMay 13 1969 Praricis Weiss and Arsexle Isa rd Inventor(s) It iscertified that error appears in the above-identified patent and that;said Letters Patent are hereby corrected as shown below:

' Column 2 line 40 "CH should read "CH Column 11, line 12, "(0.94)"should read "(0.084 moles)" Column 12, line 25, "is" should read "in"$PGNED AND SEALED JUL 1 41970 Atteat:

Edward M. Fletcher, In.

mm! E. 50mm, J'I

Attesting Officer Gomzuissioner or Pat ent.-

